The present invention relates to apparatus for injecting water vapor into an internal combustion engine and more particularly to such apparatus as will automatically increase the rate of water vapor injection with increased engine output and decrease the rate of water vapor injection with decreased engine output.
Various systems for water injection of internal combustion engines have been known heretofore since it was previously recognized that water injection is useful in connection with controlling air pollution, increasing engine efficiency so as to decrease fuel consumption, and in enabling the engine to operate with a reduced accumulation of carbon deposits, sludge, germs and the like.
Typical of one prior system is the moisturizer disclosed in U.S. Pat. No. 3,141,447 issued July 21, 1964 to P. S. Jernigan wherein water is withdrawn from a water supply reservoir and is conducted to the carburetor of the engine for introduction of the water in vapor form into the intake manifold. However, the water is mixed with hot exhaust gases prior to introduction into the carburetor and this can have an adverse effect upon the mixing ratio of the carburetor which maight necessitate frequent carburetor adjustment.
Another prior system is disclosed in U.S. Pat. No. 1,317,362 issued Sept. 30, 1919 to A. A. Friestedt. In this patent a receptacle for liquid is connected to the intake manifold of an internal combustion engine so as to conduct water vapor from the receptacle to the intake manifold. The patentee also provided for an arrangement whereby the air supply to the receptacle was controlled in order to cut off such supply until a predetermined engine speed had been attained. However, in accordance with this system there was substantially no water injection at low engine speeds since the air supply was shut off.